Reproduction

All living creatures are motivated by two overwhelming primal instincts.
These are survival of the individual and survival of the species as a whole.

In the realm of the first instinct falls the daily routine of foraging for
food, finding shelter against the hostile elements and defence against, or
avoidance of, predation.

In the realm of the second falls the annual rituals of seeking a mate,
mating and producing offspring.

Sex and reproduction amongst serpents is of necessity brief. Snakes are
loners who do not tend to live with, or care for, mates. Snakes tend to
avoid others of their kind as it means competition for food resources. They
are not usually hostile during chance meetings though. Neither is a snake
much of a mother. The young must fend for themselves the moment they are
born.

Sexual Meeting:

In spring, or when it gets warmer, sexually active males will approach any
other snake they see - and the reaction of the approached will then determine
the outcome of the encounter. If the approached is a male and it acts
aggressively a battle will usually immediately ensue. These battles
vary from species to species. Elapids and Vipers tend to indulge in a form
of ritualised wrestling and no biting takes place. Colubrids on the other
hand can get very violent and bite each other severely. Certain species
indulge in no combat but follow the female in amicable groups.

Should the approached not react in any particular manner the male snake will
then begin the preliminaries to the sexual act. Using the vomeronasal organ,
which gets its data from the tongue, the male will determine chemically
what sex and species the approached is by the pheromones emitted from its
skin. If it is not a sexually receptive female of the right species the male
will quickly move off in search of a new mate.

Snakes mating

Should the approached snake be a receptive female the male will then attempt
to mate with her. He will place his head on her back, wind his tail around
hers and attempt to join their cloacas together. However the female seldom
permits such an uncomplicated act and she usually moves off while he is
trying to mate. The male usually only succeeds after many hours - or
sometimes days - of trying.

The sexual organs of the male consist of two penises - called hemipenes.
The hemipene is covered with flexible spines. Once the male succeeds in
penetrating the cloaca of the female with one of his hemipenes it will
inflate and the flexible spines will prevent it from being easily dislodged.
The coupling usually last for an hour or two but sometimes it is as little
as a few minutes to as long as a two days. The couple generally lie still
throughout the mating but in some cases the female will pull the male along
with her as she moves. After mating it is normal for the male to stay
close by the female for a few days and then to couple again.

A hemipene

What came first? The snake or the egg?

Snake laying an egg

Approximately 70% of snake species are oviparous. This means the female
deposits a number of eggs in a carefully chosen spot. Temperature and
humidity must be just right and gravid females will travel great distances
to find the correct spot for laying their eggs.

Egg hatching - the hatchling has just cut through the egg shell with its
egg tooth

In rare instances the female
will "stand guard" over her eggs - never straying far from where they were
laid and fighting off predators who would consume them. Some cobras in India
are observed to do this. Only one snake actually builds a nest into which
the eggs are deposited - the King Cobra (Ophiphagous hannah). The female
King Cobra will coil around her nest and guard it.

Many pythons take real care of their eggs - incubating them by regulating
temperature by muscular action of their own bodies. They both care for
and protect their eggs.

Snake giving birth to live young

The other 30% of snakes give live birth. They are ovovivaparous. Which
means they hatch their eggs within their bodies. Nearly all snakes living
in cold climates use this method.

Embryonic development.

Fertilization - the ovule and the spermatozoid meeting - takes place high up in
the oviduct. (see Anatomy) The fertilised egg then
moves down into the oviduct where the uterine glands secrete substances to surround
it. The nature of these substances depends on whether the egg is to be laid or
gestated within the body. The length of embryonic development depends on species,
and within the species on temperature.

The variations are great with a range of 2 to 5 months encompassing most
species.

Fecundity.

The clutch of eggs produced by the female shows just as vast a range as
gestation times, with between 2 and 50 being within the norm. However
the usual range is between 4 and 16 eggs. As females age and increase in
size bigger clutches are produced. Another factor influencing clutch
size is the frequency of reproduction.

Most ovovivaparous snakes have a litter annually.

Growth and Maturity.

A newborn hatchling is a perfect miniature replica of the snake which
gave birth to it - except for its head which is proportionately larger.
It has to fend for itself from the moment it is born. Mortality among
infant snakes is very high and predation great.

The growth of a newborn snake is indeterminate and continuous. It depends
on availability of nutrients and frequency of feeding. Another factor
influencing the rate of growth is temperature. In the tropics snakes tend
to grow much faster than in temperate climates. All of these factors
influence sexual maturity - even within a single species.

Males tend to mature at a younger age than females. In some areas snakes
can be sexually mature at nine months while a more normal age is around 2
to 3 years. However the range is once again great. Prairie rattlesnakes
in Utah attain sexual maturity at 3 years while in Canada they only do so
at the age of seven.